Journal ArticleDOI
The power of parallel prefix
Reads0
Chats0
TLDR
This study assumes the weakest PRAM model, where shared memory locations can only be exclusively read or written (the EREW model) to solve the prefix computation problem, when the order of the elements is specified by a linked list.Abstract:
The prefix computation problem is to compute all n initial products a1* . . . *a1,i=1, . . ., n of a set of n elements, where * is an associative operation. An O(((logn) log(2n/p))XI(n/p)) time deterministic parallel algorithm using p≤n processors is presented to solve the prefix computation problem, when the order of the elements is specified by a linked list. For p≤O(n1-e)(e〉0 any constant), this algorithm achieves linear speedup. Such optimal speedup was previously achieved only by probabilistic algorithms. This study assumes the weakest PRAM model, where shared memory locations can only be exclusively read or written (the EREW model).read more
Citations
More filters
Book ChapterDOI
All Graphs have Cycle Separators and Planar Directed Depth-First Search is in DNC
TL;DR: In this article, it was shown that cycle separators can be found in O(n + e) time for any undirected graph of n vertices and e edges; in O((n + log n) log n)-time for any directed graph.
Proceedings ArticleDOI
Efficient time-slot assignment algorithms for SS/TDMA systems with variable-bandwidth beams
Suresh Chalasani,Anujan Varma +1 more
TL;DR: The authors present efficient sequential and parallel algorithms for computation of time-slot assignments in SS/TDMA (satellite-switched/time-division multiple-access) systems with variable-bandwidth beams based on modeling the time- slot assignment (TSA) problem as a network-flow problem.
Proceedings ArticleDOI
Optimal schedules for parallel prefix computation with bounded resources
Alexandru Nicolau,Haigeng Wang +1 more
TL;DR: This work shows optimal schedules for parallel pre x computation with a xed number of resources p 2 for a pre x of size N p(p + 1)=2, and presents a pipelined form of optimal schedules with d2N=( p + 1)e + d(p 1)= 2e 1 time, which takes a constant overhead of d( p 1)+1 time more than the optimal schedules.
Journal ArticleDOI
An improved algorithm for the p-center problem on interval graphs with unit lengths
TL;DR: An O(n) time algorithm is presented for the p-center problem under the assumption that the endpoints of the intervals are sorted, which improves on the existing best algorithm for the problem that has a run time of O(pn).
Journal ArticleDOI
Parallel computational geometry of rectangles
TL;DR: This paper gives parallel algorithms for a number of problems usingn processors wheren is the number of upright rectangles and the area, perimeter, eccentricity, and moment of inertia of the region covered by the rectangles inO(logn) time.